442 research outputs found

    Single-photon emission via Raman scattering from the levels with partially resolved hyperfine structure

    Full text link
    The probability of emission of a single photon via Raman scattering of laser pulse on the three-level Λ\Lambda - type atom in microcavity is studied. The duration of the pulse is considered to be short enough, so that the hyperfine structure of the upper level remains totally unresolved, while that of the lower level is totally resolved. The coherent laser pulse is assumed to be in resonance with the transition between one hyperfine structure component of the lower atomic level and all hyperfine structure components of the upper level, while the quantized cavity field is assumed to be in resonance with the transition between the other hyperfine structure component of the lower level and all components of the upper one. The dependence of the photon emission probability on the mutual orientation of polarization vectors of the cavity mode and of the coherent laser pulse is analyzed. Particularly, the case is investigated, when the total electronic angular momentum of the lower atomic level equals 1/2, which is true for the ground states of alkali atoms employed in the experiments on deterministic single photon emission. It is shown, that in this case the probability of photon emission equals zero for collinear polarizations of the photon and of the laser pulse, and the probability obtains its maximum value, when the angle between their polarizations equals 60 degrees.Comment: 5 pages, 3 figure

    Adding epoetin alfa to intense dose-dense adjuvant chemotherapy for breast cancer : randomized clinical trial

    Get PDF
    BACKGROUND: The AGO-ETC trial compared 5-year relapse-free survival of intense dose-dense (IDD) sequential chemotherapy with epirubicin (E), paclitaxel (T), and cyclophosphamide (C) (IDD-ETC) every 2 weeks vs conventional scheduled epirubicin/cyclophosphamide followed by paclitaxel (EC→T) (every 3 weeks) as adjuvant treatment in high-risk breast cancer patients. The objective of this study was to evaluate the safety and efficacy of epoetin alfa in a second randomization of the intense dose-dense arm. METHODS: One thousand two hundred eighty-four patients were enrolled; 658 patients were randomly assigned to the IDD-ETC treatment group. Within the IDD-ETC group, 324 patients were further randomly assigned to the epoetin alfa group, and 319 were randomly assigned to the non-erythropoiesis-stimulating agent (ESA) control group. Primary efficacy endpoints included change in hemoglobin level from baseline to Cycle 9 and the percentage of subjects requiring red blood cell transfusion. Relapse-free survival, overall survival, and intramammary relapse were secondary endpoints estimated with Kaplan-Meier and Cox regression methods. Except for the primary hypothesis, all statistical tests were two-sided. RESULTS: Epoetin alfa avoided the decrease in hemoglobin level (no decrease in the epoetin alfa group vs -2.20g/dL change for the control group; P < .001) and statistically significantly reduced the percentage of subjects requiring red blood cell transfusion (12.8% vs 28.1%; P < .0001). The incidence of thrombotic events was 7% in the epoetin alfa arm vs 3% in the control arm. After a median follow-up of 62 months, epoetin alfa treatment did not affect overall survival, relapse-free survival, or intramammary relapse. CONCLUSIONS: Epoetin alfa resulted in improved hemoglobin levels and decreased transfusions without an impact on relapse-free or overall survival. However, epoetin alfa had an adverse effect, resulting in increased thrombosis

    HIPEC for Ovarian Cancer: A Controversial Discussion

    Get PDF
    Peritoneal carcinomatosis is a sign of advanced disease of ovarian cancer. The prognosis of ovarian cancer is significantly improved after cytoreductive surgery with complete tumor debulking followed by platin based chemotherapy. If cytoreductive surgery results in a tumor free situation with remaining tumor less than 0.25 cm, HIPEC may further improve prognosis. Materials and methods: The results of the Krefeld study are presented and the literature is reviewed according to overall survival and progression free survival with or without HIPEC. In the Krefeld study, patients with ovarian cancer and peritoneal carcinomatosis underwent cytoreductive surgery. In patients with optimal tumor debulking, HIPEC was performed. The peri- and postoperative course was observed. Adverse events were recorded after the Clavien-Dindo classification. Results: 43 patients were treated with cytoreductive surgery and HIPEC. In all patients an optimal cytoreductive situation with remaining tumor less than 0.25 cm was achieved. HIPEC was performed with a cisplatin solution (50 mg/m2) at 41°C. The median age of the patients was 56 years (range: 32–74 years), the median peritoneal cancer index (PCI) was 13 (range: 4–21), the median operation time was 356 minutes (range: 192–507 minutes). The median time to postoperative systemic treatment with chemotherapy was 29 days (range 21–70). There was no postoperative surgically associated death. No adverse events were recorded in 16 (37.2%) of 43 patients, no grade III or IV adverse events were reported for 33 (76.7%) patients, and no grade IV adverse events were reported for 41 (95.3%) patients. Grade III adverse events occured in 19 (44.2%) of the 43 patients; a total of 29 grade III adverse events were reported in these 19 patients. Grade IV adverse events occured in 3 (7.0%) of the 43 patients; a total of 3 grade IV adverse events were reported. Two of them resulted in return to the operating room. This was a fistula of the distal small bowel caused by drainage and a revision of wound infection. Conclusion: In ovarian cancer multiple surgical procedures may be necessary in order to have macroscopically eradicated tumor tissue. Combined with HIPEC, this seems to have positive effects on the survival of patients with peritoneal carcinomatosis. Since we have no marked additional adverse events caused by HIPEC in our case series, HIPEC seems to be an additional treatment option of peritoneal carcinomatosis in ovarian cancer. This statement is strengthened by the literature review in that metaanalysis show significant improved OAS and PFS

    Towards quantum computing with single atoms and optical cavities on atom chips

    Full text link
    We report on recent developments in the integration of optical microresonators into atom chips and describe some fabrication and implementation challenges. We also review theoretical proposals for quantum computing with single atoms based on the observation of photons leaking through the cavity mirrors. The use of measurements to generate entanglement can result in simpler, more robust and scalable quantum computing architectures. Indeed, we show that quantum computing with atom-cavity systems is feasible even in the presence of relatively large spontaneous decay rates and finite photon detector efficiencies.Comment: 14 pages, 6 figure

    Cardio-metabolic risk factors and cortical thickness in a neurologically healthy male population: results from the psychological, social and biological determinants of ill health (pSoBid) study

    Get PDF
    &lt;p&gt;Introduction: Cardio-metabolic risk factors have been associated with poor physical and mental health. Epidemiological studies have shown peripheral risk markers to be associated with poor cognitive functioning in normal healthy population and in disease. The aim of the study was to explore the relationship between cardio-metabolic risk factors and cortical thickness in a neurologically healthy middle aged population-based sample.&lt;/p&gt; &lt;p&gt;Methods: T1-weighted MRI was used to create models of the cortex for calculation of regional cortical thickness in 40 adult males (average age = 50.96 years), selected from the PSOBID study. The relationship between cardio-vascular risk markers and cortical thickness across the whole brain, were examined using the general linear models. The relationship with various covariates of interest was explored.&lt;/p&gt; &lt;p&gt;Results: Lipid fractions with greater triglyceride content (TAG, VLDL and LDL) were associated with greater cortical thickness pertaining to a number of regions in the brain. Greater C reactive protein (CRP) and Intercellular adhesion molecule (ICAM-1) levels were associated with cortical thinning pertaining to perisylvian regions in the left hemisphere. Smoking status and education status were significant covariates in the model.&lt;/p&gt; &lt;p&gt;Conclusions: This exploratory study adds to a small body of existing literature increasingly showing a relationship between cardio-metabolic risk markers and regional cortical thickness involving a number of regions in the brain in a neurologically normal middle aged sample. A focused investigation of factors determining the inter-individual variations in regional cortical thickness in the adult brain could provide further clarity in our understanding of the relationship between cardio-metabolic factors and cortical structures.&lt;/p&gt

    BNP controls early load-dependent regulation of SERCA through calcineurin

    Get PDF
    Heart failure is characterised by reduced expression of sarcoplasmic reticulum calcium-ATPase (SERCA) and increased expression of B-type natriuretic peptide (BNP). The present study was performed to investigate causality of this inverse relationship under in vivo conditions in the transversal aortic constriction mouse model (TAC). Left ventricular SERCA-mRNA expression was significantly upregulated in TAC by 32% after 6 h, but not different from sham after 24 h. Serum proANP and BNP levels were increased in TAC after 24 h (BNP +274%, p < 0.01; proANP +60%, p < 0.05), but only proANP levels were increased after 6 h (+182%, p < 0.01). cGMP levels were only increased 24 h after TAC (+307%, p < 0.01), but not 6 h after TAC. BNP infusion inhibited the increase in SERCA expression 6 h after TAC. In BNP-receptor-knockout animals (GC-A), the expression of SERCA was still significantly increased 24 h after TAC at the mRNA level by 35% (p < 0.05), as well as at the protein level by 25% (p < 0.05). MCIP expression as an indicator of calcineurin activity was regulated in parallel to SERCA after 6 and 24 h. MCIP-mRNA was increased by 333% 6 h after TAC, but not significantly different from sham after 24 h. In the GC-A-KO mice, MCIP-mRNA was significantly increased in TAC compared to WT after 24 h. In mice with BNP infusion, MCIP was significantly lower 6 h after TAC compared to control animals. In conclusion, mechanical load leads to an upregulation of SERCA expression. This is followed by upregulation of natriuretic peptides with subsequent suppression of SERCA upregulation. Elevated natriuretic peptides may suppress SERCA expression by inhibition of calcineurin activity via activation of GC-A

    Generation of a wave packet tailored to efficient free space excitation of a single atom

    Full text link
    We demonstrate the generation of an optical dipole wave suitable for the process of efficiently coupling single quanta of light and matter in free space. We employ a parabolic mirror for the conversion of a transverse beam mode to a focused dipole wave and show the required spatial and temporal shaping of the mode incident onto the mirror. The results include a proof of principle correction of the parabolic mirror's aberrations. For the application of exciting an atom with a single photon pulse we demonstrate the creation of a suitable temporal pulse envelope. We infer coupling strengths of 89% and success probabilities of up to 87% for the application of exciting a single atom for the current experimental parameters.Comment: to be published in Europ. Phys. J.

    Quantum Locality

    Full text link
    It is argued that while quantum mechanics contains nonlocal or entangled states, the instantaneous or nonlocal influences sometimes thought to be present due to violations of Bell inequalities in fact arise from mistaken attempts to apply classical concepts and introduce probabilities in a manner inconsistent with the Hilbert space structure of standard quantum mechanics. Instead, Einstein locality is a valid quantum principle: objective properties of individual quantum systems do not change when something is done to another noninteracting system. There is no reason to suspect any conflict between quantum theory and special relativity.Comment: Introduction has been revised, references added, minor corrections elsewhere. To appear in Foundations of Physic
    • 

    corecore